1 Jul
2007
1 Jul
'07
12:06 p.m.
Stefan O'Rear wrote:
This is *much* easier expressed as a bottom-up traversal.
compile = transform optimize . transform eliminate
eliminate (Lam v e) = transform (abstract v) e eliminate x = x
abstract v (Var v') | v == v' = I abstract v (a :@ b) = S :@ a :@ b abstract v x = x
optimize (S :@ (K :@ x) :@ (K :@ y)) = K :@ (x :@ y) optimize (S :@ (K :@ x) :@ I) = x optimize x = x
(Here using Uniplate, mostly because it is the freshest in my mind of all of them).
Um... shouldn't that read abstract v (a :@ b) = S :@ (transform (abstract v) a) :@: (transform (abstract v) b) ? Or am I missing something?